Make Failure inherit from MaybeObject instead of Object.

src/top.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 66 matching lines @@
   void Free() {
     ASSERT(!has_pending_message_);
     ASSERT(!external_caught_exception_);
     ASSERT(try_catch_handler_address_ == NULL);
   }
 
   // The context where the current execution method is created and for variable
   // lookups.
   Context* context_;
   int thread_id_;
-  Object* pending_exception_;
+  MaybeObject* pending_exception_;
   bool has_pending_message_;
   const char* pending_message_;
   Object* pending_message_obj_;
   Script* pending_message_script_;
   int pending_message_start_pos_;
   int pending_message_end_pos_;
   // Use a separate value for scheduled exceptions to preserve the
   // invariants that hold about pending_exception.  We may want to
   // unify them later.
-  Object* scheduled_exception_;
+  MaybeObject* scheduled_exception_;
   bool external_caught_exception_;
   SaveContext* save_context_;
   v8::TryCatch* catcher_;
 
   // Stack.
   Address c_entry_fp_;  // the frame pointer of the top c entry frame
   Address handler_;   // try-blocks are chained through the stack
 
 #ifdef ENABLE_LOGGING_AND_PROFILING
   Address js_entry_sp_;  // the stack pointer of the bottom js entry frame
@@ skipping 50 matching lines @@
   static SaveContext* save_context() {return thread_local_.save_context_; }
   static void set_save_context(SaveContext* save) {
     thread_local_.save_context_ = save;
   }
 
   // Access to current thread id.
   static int thread_id() { return thread_local_.thread_id_; }
   static void set_thread_id(int id) { thread_local_.thread_id_ = id; }
 
   // Interface to pending exception.
-  static Object* pending_exception() {
+  static MaybeObject* pending_exception() {
     ASSERT(has_pending_exception());
     return thread_local_.pending_exception_;
   }
   static bool external_caught_exception() {
     return thread_local_.external_caught_exception_;
   }
-  static void set_pending_exception(Object* exception) {
+  static void set_pending_exception(MaybeObject* exception) {
     thread_local_.pending_exception_ = exception;
   }
   static void clear_pending_exception() {
     thread_local_.pending_exception_ = Heap::the_hole_value();
   }
 
-  static Object** pending_exception_address() {
+  static MaybeObject** pending_exception_address() {
     return &thread_local_.pending_exception_;
   }
   static bool has_pending_exception() {
     return !thread_local_.pending_exception_->IsTheHole();
   }
   static void clear_pending_message() {
     thread_local_.has_pending_message_ = false;
     thread_local_.pending_message_ = NULL;
     thread_local_.pending_message_obj_ = Heap::the_hole_value();
     thread_local_.pending_message_script_ = NULL;
   }
   static v8::TryCatch* try_catch_handler() {
     return thread_local_.TryCatchHandler();
   }
   static Address try_catch_handler_address() {
     return thread_local_.try_catch_handler_address();
   }
   // This method is called by the api after operations that may throw
   // exceptions.  If an exception was thrown and not handled by an external
   // handler the exception is scheduled to be rethrown when we return to running
   // JavaScript code.  If an exception is scheduled true is returned.
   static bool OptionalRescheduleException(bool is_bottom_call);
 
 
   static bool* external_caught_exception_address() {
     return &thread_local_.external_caught_exception_;
   }
 
-  static Object** scheduled_exception_address() {
+  static MaybeObject** scheduled_exception_address() {
     return &thread_local_.scheduled_exception_;
   }
 
-  static Object* scheduled_exception() {
+  static MaybeObject* scheduled_exception() {
     ASSERT(has_scheduled_exception());
     return thread_local_.scheduled_exception_;
   }
   static bool has_scheduled_exception() {
     return !thread_local_.scheduled_exception_->IsTheHole();
   }
   static void clear_scheduled_exception() {
     thread_local_.scheduled_exception_ = Heap::the_hole_value();
   }
 
@@ skipping 69 matching lines @@
   static void SetFailedAccessCheckCallback(
       v8::FailedAccessCheckCallback callback);
   static void ReportFailedAccessCheck(JSObject* receiver, v8::AccessType type);
 
   // Exception throwing support. The caller should use the result
   // of Throw() as its return value.
   static Failure* Throw(Object* exception, MessageLocation* location = NULL);
   // Re-throw an exception.  This involves no error reporting since
   // error reporting was handled when the exception was thrown
   // originally.
-  static Failure* ReThrow(Object* exception, MessageLocation* location = NULL);
+  static Failure* ReThrow(MaybeObject* exception,
+                          MessageLocation* location = NULL);
   static void ScheduleThrow(Object* exception);
   static void ReportPendingMessages();
   static Failure* ThrowIllegalOperation();
 
   // Promote a scheduled exception to pending. Asserts has_scheduled_exception.
-  static Object* PromoteScheduledException();
-  static void DoThrow(Object* exception,
+  static Failure* PromoteScheduledException();
+  static void DoThrow(MaybeObject* exception,
                       MessageLocation* location,
                       const char* message);
   static bool ShouldReturnException(bool* is_caught_externally,
                                     bool catchable_by_javascript);
 
   // Attempts to compute the current source location, storing the
   // result in the target out parameter.
   static void ComputeLocation(MessageLocation* target);
 
   // Override command line flag.
@@ skipping 138 matching lines @@
 
 class ExecutionAccess BASE_EMBEDDED {
  public:
   ExecutionAccess();
   ~ExecutionAccess();
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_TOP_H_